In a typical communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and/or user equipments (UE), communicate via a Radio Access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into areas or cell areas, with each area or cell area being served by an access node e.g., a Wi-Fi access point or a radio base station (RBS), which in some networks may also be called, for example, a “NodeB” or “eNodeB”. The area or cell area is a geographical area where radio coverage is provided by the access node. The access node communicates over an air interface operating on radio frequencies with the wireless device within range of the access node. The access node communicates over a downlink (DL) to the wireless device and the wireless device communicates over an uplink (UL) to the access node.
A Universal Mobile Telecommunications System (UMTS), comprising the UMTS terrestrial radio access network (UTRAN), is a third generation telecommunication network, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks and UTRAN specifically, and investigate enhanced data rate and radio capacity. In some RANs, e.g. as in UTRAN, several access nodes may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC), which supervises and coordinates various activities of the plural access nodes connected thereto. The RNCs are typically connected to one or more core networks.
Specifications for the Evolved Packet System (EPS) have been completed within the 3rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a 3GPP radio access technology wherein the access nodes are directly connected to the EPC core network. As such, the Radio Access Network (RAN) of an EPS has an essentially “flat” architecture comprising access nodes connected directly to one or more core networks.
The 3GPP is and has been working on standardization of the Long Term Evolution (LTE) concept. The architecture of the LTE system is shown in FIG. 1a, including access nodes, denoted as eNBs, of the E-UTRAN, and evolved packet core nodes such as MME/S-GWs. As it can be seen, an S1 interface connects eNBs to the MME/S-GW, while an X2 interface connects peer eNBs.
In existing communication networks, like LTE, system information is broadcasted by each cell containing information on how to access the network. The wireless devices download System Information Blocks (SIB) from the Downlink Shared Channel (DL-SCH), where SIB2 contains parameters needed for initial access transmission containing System information-Radio Network Temporary Identifier (SI-RNTI), Root sequence index, Zero correlation zone configuration, Physical Random Access Channel (PRACH) frequency, and PRACH frequency offset, all used by the wireless device to access the cell. The Root sequence index and the Zero correlation zone configuration are, together with the Physical Cell Index (PCI), parameters that need to be planned for optimal performance of the access to the LTE network. This could be done manually or be automated.
FIG. 1b shows a possible 5G mobility concept. A set of Access Information (AI), such as an access information list or a table with access information, comprises information necessary to access the network. The access information may comprises information such as identity of Public Land Mobile Network (PLMN), power settings, physical resource barring info etc. and may be transmitted with a periodicity e.g. 10 s or 24 s. An access node, also referred to as network node, may provide service coverage over a geographical area herein denoted service area. Multiple Access Nodes (AN), also referred to as network nodes, may comprise the same AI and each service area is associated with one or more System Identities (SID) e.g. a system signature indication indicating e.g. identity of a Transmission (TX) antenna of the access node. For example, a first small access node may be associated with a first SID, e.g. ‘1’; a second small access node may be associated with a second SID, e.g. ‘2’; a third small access node may be associated with a third SID, e.g. ‘3’; a fourth small access node may be associated with the second and third SID, e.g. ‘2’+‘3’, of different antennas. The SID is used by the wireless device to find the system and a SID value may map to an entry in the table or list of access information (AI). SID is transmitted e.g. every 100 ms, and to be energy efficient the network nodes may broadcast the AI rather infrequent, e.g. with an interval of around 10 seconds. Broadcasting AI from all antennas in every service area generates a processing overhead in the network and interference in the downlink.